Blue diamonds are even more unusual than pink ones, normally found at Rio Tinto’s Argyle mine in Western Australia.

In June last year, a massive intense blue diamond, known as The Cullinan Dream, fetched $25.4 million at a Christie’s auction in New York, breaking all records and becoming the most expensive gem of its kind ever sold at auction.

Australia’s largest diamond, a 104.73 carat stone, was discovered at Merlin, which was run by Rio Tinto and Ashton Mining between 1999-2003, before being acquired in 2014 by Merlin Diamonds, formerly North Australian Diamonds.